Every organism has certain features or characteristics that allow it to live successfully in its habitat. These features are called adaptations, and we say that the organism is adapted to its habitat. Organisms within a community compete with each other for limited resources, including water and space. Plants also compete with each other for light and minerals.
A pond ecosystem consists of a pond habitat inhabited by aquatic plants, waterside plants, microorganisms, minnows and herons. The organisms together make up a community of living things.
Habitats have limited amounts of the resources needed by living organisms and organisms can only survive if they can get enough of these resources, so they must compete for resources with other organisms. If they are unsuccessful and cannot move to another habitat, they will die.
Remember that plants make their own food using photosynthesis, so they do not compete for food. The resources that plants compete for include:
The Arctic is cold and windy with very little rainfall. Plants in the Arctic often grow very close to the ground and have small leaves. This helps to conserve water and to avoid damage by the wind.
Camels live in deserts that are hot and dry during the day, but cold at night. Their adaptations include:
large, flat feet to spread their weight on the sand
thick fur on the top of the body for shade, and thin fur elsewhere to allow easy heat loss
a large surface-area-to-volume ratio to maximise heat loss
the ability to go for a long time without water - they don't store water in their humps, but they lose very little water through urination and perspiration
the ability to tolerate body temperatures up to 42ºC
slit-like nostrils and two rows of eyelashes to help keep out sand.
Cacti in the American desert
A cactus is adapted to life in a hot climate
Cacti are well adapted for survival in the desert. Their adaptations include:
stems that can store water
widespread root systems that can collect water from a large area.
In addition, cacti have spines instead of leaves. These minimise the surface area and so reduce water loss by transpiration. The spines also protect the cacti from animals that might eat them.
Certain bacteria can live in hot springs or around deep-sea hydrothermal vents, where the water can be very hot. Certain plants grow well in salt marshes where the salt concentration is too high for most plants. For example, samphire looks a bit like a dandelion but can grow close to the sea shore.